1.Field of the Invention
This invention relates to a conveyor for separating and aligning glass sheets as they advance along a sheet movement path.
2. Discussion of the Prior Art and Technical Problems
In the use of automatic equipment for removing glass sheets from a conveyor, the glass sheets are preferably aligned with unloading equipment and separated from one another. The glass sheets are aligned with the loading equipment so that the sheets move into the same predetermined unloading position. The glass sheets are separated to eliminate glass edge damage due to edge contact.
U.S. Pat. Nos. 1,228,543 and 1,833,965 each, in general, teach the use of skew rolls for advancing bar stock from one side of a conveyor to an opposite side of the conveyor. The bar stock drops from the conveyor onto a second conveyor and are displaced into a shearing machine.
Although the use of skew rolls as taught in the abovementioned U.S. Patents are suitable for bar stock movement, there are limitations when practiced on glass sheets. For example, advancing glass sheets to a side of a conveyor and thereafter dropping them onto a second conveyor can damage the glass sheets.
In the sheet moving art, conveyors having skew rolls and a bar mounted at one side of the conveyor are known. The sheet is moved by the rolls into engagement with the bar to prevent the sheets from dropping from the conveyor.
These types of conveyors have limitations especially when used for glass sheets. For example, as the sheets engage the bar and are continually advanced by the conveyor, the friction between the side of the sheets and the bar can cause a sheet to rotate. This sheet rotation can cause edge contact between adjacent sheets resulting in edge damage.
U.S. Pat. Nos. 268,629; 1,447,649; 1,812,876 and 3,011,211 each teach, in general, the use of conveyor rolls having a constant shaft rotational speed and different diameters to provide each of the rolls with a different surface rotational or peripheral speed for accelerating or decelerating articles, e.g., glass sheets. Although each of the patents are suitable for their stated purposes, there is no teaching of a conveyor for separating and aligning sheets as they advance along a sheet movement path.
U.S. Pat. Nos. 1,761,199; 1,848,114; 1,879,720; 2,765,065 and 3,456,026 teach, in general, the use of conveyors for advancing different types of material, e.g., glass sheets, dough or boxes. Each of the conveyors teach in one form or another accelerating the material along the conveyor by having different rotational speeds acting on each of the rolls or by changing the rotational speed of the rolls.
There is no teaching in any of the above-identified patents for advancing glass sheets along a conveyor while aligning and separating the glass sheets.
In packing glass sheets, it is preferred to align the sheets and pull a gap between the sheets to prevent edge chipping. There are no apparatuses taught in the prior art that can perform both these functions and therefore it would be advantageous to provide such a conveying system.